Frasor, 36, has a 3.34 ERA in 38 games this season with 30 strikeouts and 14 walks in 29 2/3 innings. He has a career 3.65 ERA over 624 games with the Blue Jays, White Sox and Rangers, all out of the bullpen.

Patton, 26, had a 4.08 ERA in 34 games with Triple-A Omaha this season with 60 strikeouts and 22 walks in 46 1/3 innings. He's never appeared in an MLB game.

The Royals said Frasor would be active for Friday's series opener in Boston.